Unlike nice desktop, iphone in MAIL, my inner folders I create are expanded, not collapsed.

On the Desktop, 10 main folders for an email account, and in there say each has 20 inside. On desktop by default they collapse.-- hunky dory.

I asked Apple rep while back why iphone not collapse, just said way it is.

Is there a solution, 3rd party app to collapse Mail folders on IOS?

As it TOTALLY UNUSABLE / impossible to scroll though my hundreds of expanded folder to find things on iphone IOS Mail app. Thanks